A smokers' lobby group has called for proof that second-hand smoke causes ill health.
Bars that serve food will have to ban smoking under new laws
Forest has issued a direct challenge to England's Chief Medical Officer to prove claims that passive smoking kills hundreds of UK people each year.
It says proposed smoking bans were based on scientific studies that had failed "spectacularly" to establish any significant link to ill-health.
Anti-smoking groups maintain that the evidence showed passive smoking kills.
A study in the British Medical Journal this month said second-hand smoke claims more than 11,000 lives a year in the UK - much higher than previously thought.
Doctors have been calling for a complete ban on smoking in public places since November's Public Health White Paper proposed a partial ban in public places, giving pubs which do not serve food exemption from the ban.
President of Forest, Lord Harris of High Cross, said: "The attempt to ban smoking in all public places would be understandable if it was based on incontrovertible scientific evidence of harm to others.
"But this is very far from the truth. The truth is that the dozens of studies conducted around the world over the past 25 years fail spectacularly to yield any reliably stable, uniform or statistically significant link between lifetime exposure to environmental tobacco smoke (ETS) and lung cancer in non-smokers."
He accused anti-smoking groups of twisting and stretching risk calculations beyond breaking point.
He challenged Sir Liam Donaldson to "face up" to questions surrounding claims such as smoking bans are an economic success and that ETS exposure can be measured reliably.
He also called for government to appoint an independent expert panel to establish and publicise the true facts about passive smoking.
Ian Willmore, from Action on Smoking and Health, said: "The government has already established an independent committee to look at the evidence on passive smoking.
"It is called the Scientific Committee on Tobacco and Health, it is made up of 15 of the most eminent medical scientists in Britain and it reported in November last year that exposure to other people's smoke increases your risk of getting lung cancer and heart disease, in both cases by about a quarter.
"Forest has no interest whatever in scientific evidence or independent advice. It is paid by the tobacco industry to deny the truth that other people's tobacco smoke is a risk to your health.
"It has no credibility on this issue and its pronouncements do not deserve to be taken seriously," he said.
That view was echoed by Dr Vivienne Nathanson, head of science and ethics at the British Medical Association.
She said the tobacco industry's refusal to accept the dangers associated with passive smoking would result in "the sabotage of the health of people exposed to passive smoking all over the world."
Jean King, director of tobacco control at Cancer Research UK, said: "There is an international consensus among doctors, nurses and medical research experts that second hand smoke kills innocent people. Only people who work for or receive money from the tobacco industry deny this link. Forest is such a group."